Alternating current (AC) electric motor systems powered from direct current (DC) energy sources are widely used today. Electrical motor propulsion systems for vehicles where the DC energy source is a battery are well known. Stationary DC to AC motor propulsion systems are also widely used. The control systems used within such propulsion systems monitor and control the current flowing to each phase of the poly-phase motor. The current sensors used in such systems are not always as accurate as desired or their accuracy may change with time as the system ages. Prior art motor control systems have not been able to distinguish between normal operating errors and errors caused by current sensor faults. When sensor errors or faults go undetected, the system controller and/or the propulsion motor itself may be damaged and system users may be exposed to hazards.
Accordingly, it is desirable to provide an improved control system and method for detecting phase current sensor errors due to sensor fault and, where appropriate, taking remedial action. In addition, it is desirable that the apparatus and method for detecting such sensor errors and taking remedial action be simple, rugged and reliable and be adapted to being retrofitted to existing systems. Furthermore, other desirable features and characteristics of the present invention will become apparent from the subsequent detailed description and the appended claims, taken in conjunction with the accompanying drawings and the foregoing technical field and background.